As an example of materials of components constituting aircraft, composite materials such as FRP are widely used. Also, an ultrasonic testing device is widely used to non-destructively test (inspect) internal flaws (cracks or defects) present in composite material components and to determine whether or not the components are healthy (flawless) (e.g., see Patent Literature 1).
In testing of flaws using the ultrasonic testing device, a probe generates an ultrasonic sound wave while the probe is moved along a surface of a composite material component to scan the composite material component. The generated ultrasonic sound wave travels through the interior of the composite material component and reaches a bottom surface of the composite material component or a flaw portion in the interior of the composite material component. The ultrasonic sound wave is reflected there and returns to the probe. The ultrasonic testing device obtains data relating to plural kinds of test indices such as intensity of the reflected sound wave and a time of flight (hereinafter referred to as “TOF”) which passes from when the ultrasonic sound wave is generated until the reflected sound wave is received by the probe, based on the reception of the reflected sound wave in the probe.
The determination assist system generates determination images which visualize the interior of the composite material component based on these data. The determination images include, for example, a planar image (hereinafter referred to as “C-AMP image”) which is a planar gradational image displayed according to the intensity of the reflected sound wave, a planar image (hereinafter referred to as “C-TOF image”) which is a planar gradational image displayed according to a depth of a reflection source obtained based on TOF and a sound velocity, etc. An inspector identifies what kind of internal flaws are present and to what degree the internal flaws are present, in the composite material component, with reference to these plural images, and thereby determines whether or not the composite material component is healthy.
Non-patent Literature 1 discloses that a C-AMP image represented as a gray scale image and a C-TOF image represented as a color image are superposed together, to generate a determination image which is a color and gray-scale image.